Role of hexagonal boron nitride in protecting ferromagnetic nanostructures from oxidation

TL;DR

This study demonstrates that hexagonal boron nitride effectively reduces oxidation in ferromagnetic nanostructures, potentially enhancing the longevity and performance of spintronic devices.

Contribution

It provides experimental evidence that ex-situ transferred hBN acts as an oxidation barrier for ferromagnetic nanostructures, a novel application for device protection.

Findings

hBN reduces oxidation rate of ferromagnetic nanostructures

hBN can serve as an ultra-thin protective layer

Oxide thickness is significantly lower with hBN coverage

Abstract

Ferromagnetic contacts are widely used to inject spin polarized currents into non-magnetic materials such as semiconductors or 2-dimensional materials like graphene. In these systems, oxidation of the ferromagnetic materials poses an intrinsic limitation on device performance. Here we investigate the role of ex-situ transferred chemical vapour deposited hexagonal boron nitride (hBN) as an oxidation barrier for nanostructured cobalt and permalloy electrodes. The chemical state of the ferromagnets was investigated using X-ray photoemission electron microscopy owing to its high sensitivity and lateral resolution. We have compared the oxide thickness formed on ferromagnetic nanostructures covered by hBN to uncovered reference structures. Our results show that hBN reduces the oxidation rate of ferromagnetic nanostructures suggesting that it could be used as an ultra-thin protection layer in future spintronic devices.